Preparation of a supported h3po4 catalyst



Patented Oct. 7, 1952 UNITED .STATES P TENT former Y Julian M. Mavity,Hinsdale,'Ill., assignorto Universal. Oil Products Company, Chicago,..111., a

' corporation of Delaware No Drawing. Application June 14, 1949,

Serial No. 99,122' I app a ra- 12 Claims. (01. 252-435) ducing ahydrocarbon conversion catalyst which has a high resistance to crushingduring use.

Another object of this invention is a highly active catalyst suitablefor use in'the polymerization of olefinic hydrocarbons and in otherhydrocarbon conversion reactions involving olefins.

Oneffspecific embodiment of this invention re lates to a process formanufacturing'a solid catalyst which comprises mixing a phosphoric acid,a siliceous adsorbent, and an Oxygen-containing organic. siliconcompound selected froni' the members of'the group consisting of an alkylan additional embodiment of this invention relatesto a process formanufacturing .a solid catalyst which comprises mixing a phosphoricacid, a siliceous adsorbent, and a polymeric dialkyl siloxaneto form acomposite, andcalcining fsaidcomposite.

Another embodiment of this invention relates composite.

to a process for manufacturing a, solid catalyst which comprises mixinga. phosphoric acid,v a

siliceous adsorbent, and a polymeric dimethyl siloxane to form acomposite, and calcining said composite. V v

V .A further embodiment of this invention relates to a process formanufacturing a solid catalyst which comprises mixing pyrophosphoricacid, diatomaceous earth, and a polymeric dimethyl siloxane to form acomposite, and calcining said .The essential and active ingredient ofthe solid catalystswhich are manufactured, by the present process foruse inorganic reactions is an acid of phosphorus, preferably one inwhich the phosphorus has a valence of 5, Theacid; may constitute toabout or moreof thecatalyst mixture ultimately produced, and in mostcases is over 50% by weight thereof. Of the various acids of phosphorus,orthophosphoric acid (H3PO4) and pyrophosphoric acid (H 4P2O'z) findgeneral application in .the- I primary, I mixtures, due mainly to theircheapness and to the readiness with which they may be produced althoughthe inventionis not restricted ,to' their use but may employ any o f theotherlacids vof phosphorus insofar as ,they are adaptable. It is notintended to infer, however, that thediffer ent acids of phosphorus,which maybe employed will produce catalysts which have identical effectsupon any given organic reactions as each of the catalysts producediromdifferentacids and by slightly variedprocedure will exer its owncharacteristic action.v

In using orthophosphoric acidjas a ingredient, different concentrationsof the aquemj spliltion mat em ye o arm mat'ely 75 to or acidcontainingsome e pbqephorus pemox m v be u ed. this is meant that the ortho acidmay contain .aidefinite rce a .o i e P m d cor esp nd to h imar pha ofydr i nl the o rtho-phosphoric acid. Within these; com ,centrationranges, the acids will be liquids of varying viscositiea andreadily mixed with ad by the formula HP3O10 may also be used as a starting materialfor preparation of the catalysts of this invention. These catalyticcompositions may also be prepared from the siliceous materials mentionedherein and phosphoric acid mixture containing orthophosphoric,vpyrophosphoric, triphosphoric, and other polyphosphoric acids.

Another acid of phosphorus which may be employed in the manufacture ofcompositecata:

lysts according to the present invention is tetraphosphoric acid. It hasthe general. formula HsP4O13 which corresponds to the double oxideformula 3H2O.2P2O5 which in turn may be considered as the acid resultingwhen three molecules of water are lost by four molecules oforthophosphoric acid I-IaPOr. The tetraphosphoric acid may bemanufactured by the gradual and controlled dehydration by heating oforthophosphoric acid or pyrophosphoric acid or by adding phosphoruspentoxide to these acidsin proper amounts. When the latter procedure isfollowed, phosphoric anhydride is added gradually until it amounts to520% by weight of the total water present. After a considerable periodof standing at ordinary temperatures, the crystals of thetetraphosphoric acid separate from the-viscous liquid and it is foundthat these crystals melt at approximately 93 F. and have a specificgravity of 1.1886, at a temperature of 60 F. However, it is unnecessaryto crystallize the tetraphosphoric acid before employing it inthepreparation of thes'olid catalysts inasmuch as the crudetetraphosphoric acid mixture may be incorporated with the siliceousadsorbent and other catalyst ingredient.

The materials which may be employed asadsorbents orcarriers for acids ofphosphorus are divided roughly into two classes. The first classcomprises materials of-predominantly siliceous character and includes;diatomaceous earth, kieselguhr, and artifically prepared porous silica.The second class of materials which may be em:- ployed either alone orin conjunction with the first class comprises generally certain membersof the class of aluminum silicates andfincludes such naturally occurringsubstances as various fullers earths and clays, such as bentonite,montmorillonite, acidtreated clays, and the like. Each adsorbent orsupporting material which may be used will exert its own specificinfluence upon the net effectiveness of the catalyst com posite whichwill not necessaril-ybe identical with "that of other members of theclass;

The oxygen-containing organic silicon compounds used as additives orstrengthening agents for the preparation ofsolid phosphoric acidcatalysts as set forth herein are selected from "the containing from 1to about 5 carbon atoms, although these alkyl groups may also containmore than 5 carbon atoms. The alkyl orthosilicates preferred for use inthis process include methylorthosilicate, ethylorthosilicate, and thepropylorthosilicates. Other oxygen-containing organic compounds ofsilicon which may be used in my catalyst production process may bereferred to as siloxanes or as silicones. These compounds includerelatively high molecular weight polymeric dialkyl siloxanes having theconsistency of oils, resins, and greases. The terms silocones" andsiloxanes are general terms which are descriptive of organic siliconcompounds containing both carbon-silicon linkages andsilicon-oxygensilicon linkages. Y

silicones usable in this process areof three types, corresponding to:(1) the dehydration product of a silanol of the formula RsSiOI-I whichmay be called a monosilanol (2) the dehydration product of a silane-diolof the formula R2Si(OH) 2 and (3) the dehydration product of asilane-triol represented by the formula RSi(OH)3. The formulas of thesedifferent silanols and of their corresponding dehydration products,which are known as silicones and also as siloxanes, are listedphosphoric acid, triphosphoric acid, or tetraphosphori'cacid, and asiliceous adsorbent containing an added oxygen-containing organicsilicon compound selected from the members of the group consisting of analkyl orthosilicate and a siloxane. These mentioned starting materialsused in this catalyst preparation process are subjected to thesuccessive steps of mixing the siliceous adsorbent with the addedoxygen-containing organic silicon compound, and thereafter mixing thephosphoric acid with the finely divided relatively inert carriercontaining the oxygen-containing organic silicon compound; This mixingoperation is generally carried out at a temperature of from about 50 toabout 450 F. to form an aggregate, the acid ordinarily being in majorproportion by weight. Also the oxygencontaining organic silicon compoundmay be added first to the phosphoric acid, or the'catalyst ingredientsmay be mixed in any desirable order.

The resultant aggregate is a slightly moist to almost dry material whichupon being compressed, becomes sufficiently plastic that it can beextruded and formed into shaped particles. The resultant particles arethen calcined. at 'a temperature of from about200 to about 1000 F. for atime of from about, 0.25 to about 10 hours to form a substantiallysolidmaterial. The calcining may be carried out by heating the catalystparticles in a substantially inert gas, such as air,

nitrogen, and the like.

The resultant catalyst which has-been calcined is active for promotingpolymerization ofgoleflnic hydrocarbons particularly for polymerizingnormaterial charged.

mally gaseous olefinic hydrocarbons to form normally liquid hydrocarbonssuitable for use as;- constituents of gasoline. When employed in themers, the calcined catalyst formed as herein set forth, is preferablyemployed as a granular layer e in a heated reactor, which is generallymade from steel, and through which the preheated hydrocarbon fraction isdirected. Thus the solid catalyst of this process may be employed fortreating mixtures of olefin-containing hydrocarbon vapors to effectolefin polymerization, but this 553K118".

catalyst may also be used at operating conditions; suitable formaintaining liquid phase operation during polymerization of olefinichydrocarbons,

tical, cylindrical treating tower and the olefin-.

containing gas mixture is passed downwardly therethrough at atemperature of from about 350 to about 550 F. and at a pressure of 100to about 1500pounds per square inch when dealing.with'iolefln-containlng materials such as stabilizer. reflux which maycontain from approximately110 to 50% or more of propylene and butylene.When operating on a mixture comprising essentially butanes andbutylenes, this catalyst is eifective at conditions favoring the maximumutilization of both normal butylenes and isobutylene which involvesmixed polymerization at temperatures of from approximately 250 toabout325? F. and at pressures oifrom about 500 to about 1500 pounds persquare inch.

In utilizing the catalysts of this inventionfor Lpromotingmiscellaneousorganic reactions, the

catalysts may be employed in, essentially the same way as they are ,usedwhen polymerizing olefins, in case the reactions are essentially vaporincluding polymerization of oleflns as already mentioned. Typical casesof reaction in which the present type of catalystmay be used are thealkylation of cyclic compounds with olefins, the cycliccompoundsincluding aromatics, polycyclic compounds, naphthenes, and phenols;condensation' reactions such as those occurring. between ethersandaromatics, alcohols and aromatics,

phenols andaldehydes, etc;; reactions involving the hydro-halogenationof unsaturated organic compounds, isomerization reactions, esterformation bylthe interaction ofcarboxylic acids and olefiiis. and thelike. The specific procedure for utilizing the present type of catalystsin miscellaneous organic reactions will be determined -=bythechemicaland physical characteristics and the-phase of the reacting constituents.

"Di1riiig use of'the'secatalysts in vapor phase polymerizations andother vapor phase treatments of organic compounds, it is often advisable'to' a'dd small amounts of moisture to prevent excessive'dehydration-andsubsequent decrease in "catalyst activities. In ordertosubstantially-prevent loss of water from the catalyst an amount ofwateror water vaporsuch as steam is added to the chargedolefin-containing gasso as'to subntially balance the vapor pressure of the cata- This amountof water vapor varies from by volume of the'organio Solidphosphorici..acid catalysts which have been preparedheretoforebycalcining composites of a' siliceous .ia'dsorbentnanda phosphoric acidconversion of olefinic hydrocarbons into poly frequently; lose theirvactivities during polymerization use and alsoIsu-ffef a marked decreasein crushing strength. due .lto softening of the cata- 'lyst.Suchsofteningof fthelcatalyst. also results in short catalyst life'inasmuchas the catalyst towers become plugged during use. In thisprocess, I have found thatcatalysts of high crushing strengths may beproduced by adding to the composite of phosphoric acid and diatomaceousearth a relatively small amount of an oxygen-containjingor'ganic siliconcompound selected from the members of the. group consisting of an alkylorthosilicate and a siloxane, this amount being generally not more thanabout 10% and preferably from about 0.5 to about 5% by weight of thecatalyst mixture. Such a catalyst containingan organic silicon compoundalso has a good crushing strength after it has been used in thepolymerization reaction. Pyrophosphoric aciddiatomaceous earthcomposites to which the above-indicated amounts of, I an oxygen-contain-.ing organicisilicon compound has beenadded and then the resultantcomposite has been dried and calcined .have, been, found to producecatalysts having, a high crushing strength, t his strengthbeingwmuchhigher than that of similar catalyst materials prepared fromphosphoric acidandth e samesiliceous jadsorbent, but in the, absence ofthe oxygen-containing organic silicon; compounds. These catalysts havebeen tested in converting propylene into propylene polymers in rotatable .steel autoclaves and. havebeen found toretain a highcrushingstrength; after such polymeriza- .tionv use inwhichfrom 25 to50%;of the propylene charged is converted into liquid lproducts. 1 Accorn b his ocess hi hl a t v a alysts'Of good structural strength .areproduced .byjmixing from about 50 to about by weight of a phosphoricacid, from aboutl5 to about 49.5% by weight of a siliceous adsorbent,and from, about-0.5;toaboutj10% by weight .of an, oxygen-containing-organic silicon compound] s lec d r m zn me s of ro p consisting ofanalkyl orthosilicate and a siloxane toform a composite, shaping saidcomposite into particles: drying .said particles at a temperature offrom-about 20 0 to about,500 F., and calcining-the dried particles at atemperature, of from "about-500? to aboutlOQOi F. for a time of fromabout 0.25 to about 10 hours.

v;.The' following examples of the preparation of catalysts comprisedwithin the scope of this in- .vention'. and the results obtained-intheir use for: catallyzingthe polymerization, of propylene arecharacteristic,- although the exactdetails setfiforthinthese examplesare not to be construed as. imposing undue limitations uponthe generallybroad scope. of, the invention. H

Table I shows comparative results obtained in autoclave tests onpolymerization;catalysts prepared from vorthophosphoricacid-diatomaceous earth and various. amounts of an oxygen-containing.organic siliconcompound These cataz lyst act-ivityi tests wereicarriedout by placing l0 grams of5x5 mm. pellets .ofmcatalyst and grams of apropane propylene mixture (SO-55% propylene content) in a rotatablesteel autoclave -of850 cc. capacity which was then rotated at atemperature of. 450 F. for 2 hours. At the end of this time,determinations were made to indicate thepercentage conversion ofpropylene into "liquid polymers TABLE I silicon compound.

Test Conditions: 10 grams catalyst pellets, 100 grams propane-propylenemixture (52-.55 mole percent propylene), malntaine'd'ior two hours at atemperature 450 F.in:an-850 cc. rotating autoclave.

' iCrushingstre th, tMate gialilddeg to 1rlnlxlemanation Yemen lbs. ng

ureo or o-p osp ore and diatomlzlcleous I I 23%.; B r AM can e ore r F.Hours Use Use j1--; '1%(EtO)(Sl 860 1 4o 26.6 21+ 2 1% SiIicone FIuid.850' 1' 28' 26.4+ 726.4%- 3 5% Silicone Fluid 680 1, 25, 24.3-l. .24. 8+4 1% Silicone Resin 860 i 32- 25. 6+ 27+ 5% SlllconeResln .i 680 l; 30,1 .2-H 2225+ 6 d0 860 l 28 26. 3+ 27+ 7 1% Silicone Grease 860 '1 30 7+27+ '8- 5% Silicone Grease .i- 680 11 '25; 233+ v 20.-:4+

Outstanding among these catalysts prepared from organic siliconcompounds 'in'which oxygen is present is the catalyst prepared by adding1% by weight of ethylorthosilicate to a composite or orthophosphoricacid'and diatomaceous earth'followed by calcining the composite at atemperature of 860 F. for a time of one hour. 'This catalyst convertedof the propylene into liquid polymers, it had an average crushingstrength of 26.6 lbs. before use and an after crushing-strength of 27lbs.

Other catalysts prepared from orthophosphoric acid, diatomaceous earth,and either 1% or 5% of silicone fiuid'which is a polymeric dimethylsiloxane, gave catalysts which after calcination at 680 F. and 860 F.had activities "of 25 to 28% propylene conversion and crushingstrengths-both "before and after use o'f irom 24 to 26 pounds.

' Similar catalyst composites in'w hich orthophosphoric acid anddiatom'aceous earth were mixed with 5% 'by weight oi s'ilicone'resinswere c'alcinedlfor one hour at temperatures of 680 F. and"8(i0"F. The resultant-catalysts-effected the polymerization of iirom 28 to30:% for 'Ith'e propylene present in the autoclave tests. The

crushing strength of'these'catalysts before use were from'25'to 26pounds whil'e theaitert use crushing strengths were'--22 and 27 pounds lrespectively.

' Other solid polymerization catalysts "were formed fromorthophosphoricacid diatomaceous earth 'and from l 't'o 5% b'y weight oi.'silicone"grease. 'Ihese catalysts "calcined :at :tempera- 'tures"of"680 and 860Fnfor one'hourzhad prop'yleneconversion activities betweenfls canal-30%before use crushing strength-M22210 27 pounds,

and after use 'c'r-ushing stren'gth ioi 20 :to :27 pounds as indicatedin Table I.

In comparison-with the above indi'catedicata- 'lysts, a commercial-polymerizati'on:catalyst man- -u'iacture'd from pyrophosphoric acid anddiatomaceous earth and c'alcined1'for tone :hour at a temperature of8601had7anfiriitial crushing strength of 16 poundsand'antaiterzuse-crushing strength of 9 po'unds.

l 'olaim as my: invention: r v

l. A process for manufacturing:assolidx catalyst which comprises mixingfro'm abouttoeabout 75% by weight 'ofaphosphoric*acid, from-about -l 5t0about 49.5% by weightxofiaz'siliceousadsorbent, and from about 0.5to':about:10.% @by weight of an oxygen-containing organic siliconcompound selected from the group consisting of an alkyl orthosilicateand a siloxane to form a composite, and calcining said composite.

dimethylsiloxane.

6. 'A process for manufacturing a solid catalyst which comprises mixingfrom about 50 to about by weight of a phosphoric acid, from about 15 toabout 49.5% by weight of a siliceous adsorbent, and from about 0.5 toabout 10% by weight of an oxygen-containing organic silicon compoundselected from the group consisting of an alkyl orthosilicate andaisiloxane to formi'a composite, and calcining said composite :at atemperature of fromabout 200 to about 1000 F.

7. A process for manufacturingasolid catalyst which comprises mixingfrom about ;50 :to about 75% byweightrof .a phosphoric acid,;from about.15 'to about 49.5% by weight of a vsiliceous :adsorbent, and from about0.5 to about 10% by weight of an oxygen-containing organic'siliconcompound selected from the group consisting of an alkyl orthosilicateand :a siloxane to form a composite, shaping said compositeintoparticles.

rand calcining said particles at a temperature 10f from'about 200 toabout 1000 .F. for a time-0f from about 0.25 to about 10 hours. I

8. Agprocess for manufacturing a;solid catalyst which comprises:mixingfrom about 50 to-about 75% by-weight ofaphosphoric-acidfiromabout .15 to about 49.5% by weight of a siliceousadsorbent, and from about 0.5 to about 10% by weight of van alkylorthosilicateto form a com- ;posite, shapingsaid composite intoparticles, and calcining said particles at a temperature of from about200 to about 100091.

-9, Aprocess for manufacturing a vsolid catalyst which comprises mixingfrom about.50 to about 7 5% by weight of a phosphoric acid, from about15 to about 49.5% by weight of ra sillce'o'us adsorbent, and from. about0.5.to about 10% by weight of a siloxane to form a .composite,.sbapingsaid composite into particles, and calcining sad particles at atemperature of from about 200 to about 1000 F.

10. A process for manufacturing a solid catalyst which comprises mixingfrom about 50 to about 75% by weight of a phosphoric acid, from about 15to about 49.5% by weight of a siliceous adsorbent, and from about 0.5 toabout 10% by weight of a polymeric dialkyl siloxane to form a composite,shaping said composite into particles, and calcining said particles at atemperature of from about 200 to about 1000 F.

11. A process for manufacturing a solid catalyst which comprises mixingfrom about 50 to about 75% by Weight of a phosphoric acid, from about 15to about 49.5% by weight of a siliceous adsorbent, and from about 0.5 toabout 10% by weight of a polymeric dimethylsiloxane to form a composite,shaping said composite into particles, and calcining said particles at atemperature of from about 200 to about 1000 F.

12. A process of catalyst manufacture which comprises mixing from about50 to about 75% by weight of pyrophosphoric acid, from about 15 to about49.5% by weight of diatomaceous earth, and from about 0.5 to about 10%by weight of an 10 oxygen-containing organic silicon compound selectedfrom the group consisting of an alkyl orthosilicate and a siloxane at atemperature of from about 50 to about 450 F. to form a composite,shaping said composite into particles, and

calcining said particles at a temperature of from about 200 to about1000 F. for a time of 0.25 to about 10 hours.

' JULIAN M. MAVlTY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. A PROCESS FOR MANUFACTURING A SOLID CATALYST WHICH COMPRISES MIXING FROM ABOUT 50 TO ABOUT 75% BY WEIGHT OF A PHOSPHORIC ACID, FROM ABOUT 15 TO ABOUT 49.5% BY WEIGHT OF A SILICEOUS ADSORBENT, AND FROM ABOUT 0.5 TO ABOUT 10% BY WEIGHT OF AN OXYGEN-CONTAINING ORGANIC SILICON COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN ALKYL ORTHOSILICATE AND A SILOXANE TO FORM A COMPOSITE, AND CALCINING SAID COMPOSITE. 